Photographic enlarger



Jan. 21, 1941. 5, ss 2,229,284

PHOTOGRAPHIC ENLARGER Filed March 22, 1939 3 Sheets-Sheet 1 GMW lNVENTO Jan. 21, 1941. F ssm 2,229,284

PHOTOGRAPHIC ENLARGER Filed March 22, 1939 3 Sheets-Sheet 2 Jan. 21, 1941. ssm 2,229,284

PHOTOGRAPHIG ENLARGER Filed March 22, 19:59 3 Sheets-Sheet 3 FIG.7

FIG.6

lNVENT R Patented Jan. 21, 1941 UNITED STATES PATENT OFFICE PHOTOGRAPHIC ENLARGER Gustave Fassin, Grosse Pointe, Mich, assignor to International Industries, Inc., Ann Arbor, Mich, a corporation of Michigan Application March 22, 1939, Serial N 0. 263,397

8 Claims. (01. 8824) The present invention relates to optical pro- A bracket 24 is suitably fixed on the easel l Jection apparatus for photographic enlarging. by screws or bolts 25 and a vertical column 26 is One of the objects of the present invention is secured in the bracket 24. A carriage 21 is slidto provide a simple, efficient and accurate photoably mounted on the column 26. The carriage graphic enlarger. Another object is to provide a 2'! is raised and lowered by means of a wheel 26 photographic enlarger which may be readily which engages in a groove 29 formed in the colbrought into exact focus. A further object is umn 26. Preferably both the wheel 28 and groove to provide a remote control focussing mechanism 29 are tapered and knurled to insure positive enfor a photographic enlarger. Still another object gagement.

"' is to provide a photographic enlarger having a The wheel 28 is fixed on a shaft 32 and extends 10 focussing microscope on the easel and a focus through a vertical slot 3| in the carriage 26. Two control mechanism adjacent the microscope. bearing straps 33 fastened to the carriage 26 by These and other objects and advantages reside bolts 34 hold the shaft 32 in horizontal position.

in certain novel features of construction, arrange- These straps 33 are pressed against the shaft 32 ment and combination of parts as will hereinby springs 35and thus the wheel 28 is pressed 15 after be more fully set forth and pointed out in firmly into the groove 29. Two knobs 36 secured the appended claims. on the ends of the shaft 32 serve to rotate the Referring to the drawings: shaft and raise or lower the carriage 21 on the Fig. 1 is a perspective view of my new photocolumn 26. The friction between the column 26 graphic enlarger. and the wheel 28 and carriage 21 holds the car- 0 Fig. 2 is a vertical section thereof. riage in adjusted position on the column. Fig. 3 is a section taken on line 3-3 of Fig. 2. The carriage 21 is formed with two vertical Fig. -4 is an enlarged fragmentary section showside fins 36' to which a hollow housing 31 is suiting the connection between the lamp and reflecably attached as, for example, by screws or bolts tor housings. 38. This housing 31 extends forwardly over the Fig. 5 is a section taken on line 5-5 of Fig. 3. board or easel l5 and is formed with openings 39 Fig. 6 is an enlarged fragmentary section of and 40 in its lower wall. Forwardly of these openthe projector optical system. ings 3B and 40, the housing 31 has two internal Fig. 7 is a vertical section of the film gate. baiile walls 4| and 42 which permit the free paso m Fig. 8 is an enlarged vertical section of the sage of air but act as a light trap. focussing pulley. A lamp casing 43 is suitably fastened in the Fig. 9 is a vertical section of a modified form open front end of the housing 31 by screws or of focus control mechanism. bolts 44 and the top of the lamp casing 43 is closed I A preferred form of my invention is illustrated by a door 45 pivotally secured on the housing in the drawings wherein l5 designates a flat 31. The door 45 is formed with a plurality of board or easel supported on three or more spaced openings to permit the escape of heat as is well feet Hi. This easel I5 may be similar to the easel known in the art. A light source 46 is suitably described and claimed in my copending applicasecured in the lamp chamber 43 and is supplied tion Serial No. 258,665 filed Feb. 27, 1939, for with current through a wire or cable 41,

' Photographic printing easel. The front wall 48 of the lamp chamber 43 has 40 The easel l5 has a central aperture ll beneath a forwardly extending flange 43 surrounding a which is secured a tube l8 containing a reflector central aperture 50. A reflector housing 5| is I! for directing light from the aperture I I horiattached to the wall 48 of the lamp chamber 43 zontally through a microscope objective 20. A by a plurality of bolts 52. This reflector housing second reflector 2| directs the light upward behas a central opening 53 larger than the flange yond the edge of the board I5 and the image 48 and is held in spaced relation to the lamp formed by the objective 20 is observed by means chamber 43by non-conducting washers 54. Thus of an ocular consisting of the lenses 22 and 23. the reflector housing is insulated from the lamp I prefer to make this microscope of such power chamber and the flange 49 serves as a baflle or that the silver grains on the film are resolved and trap to prevent the passage of stray light from 50 thus the enlarged image may be focussed with a the lamp chamber 43 to the easel l5. high degree of accuracy. In focussing, a target A bracket or frame 55, secured at one end to a is used and this target occupies the exact plane bolt 52 and at the other to the floor or bottom of the sensitive surface of a photographic printing of thehousing 5|, carries a reflector 56 which rep pe ceives light from the lamp 4s, and directs it downward through an aperture 61 in the bottom of' the housing 6|. This reflector 66 is preferably formed of a heat conducting material such as metal, and its rear surface is preferably black to increase the radiation from the reflector to the walls of the housing 6|. The housing 6| is, in turn, provided with a series of radiating fins or ribs 68. The front wall 69 of the housing 6| is removably attached in position by screws 69.

Directly beneath the reflector 66 and above the aperture 61, the housing 6| has a cylindrical portion 62 within which, a lens cell 69, carrying condensing lenses 64, is slidably mounted. This cell 69 is moved vertically in the portion 62 until the light from the lamp 46 is focussed on the film and is then locked in position by a set screw 66.

Beneath the aperture 61, and in spaced relation to the bottom wall, the housing 6| carries a sleeve 66 which may be formed integrally with the housing. The sleeve 66 has a fiat plate 61 at its upper end and this plate 61 is formed with an aperture 92. The film gate shown in Fig. 7 is removably positioned between the plate 61 and the bottom wall of the housing 6|. The film gate consists of a bottom plate 69 and a top plate 69 pivotally secured together along one edge by a hinge 19. The two plates 69 and 69 are formed with alined central apertures 1I and 12 respectively, of the same size as the picture portion of the film to be enlarged. The upper plate 69 has a longitudinal recess 19 of the same width as the film, and the lower plate 68 has projections 14 which engage the edges of the film and hold the film flat in the recess 13 across the apertures 1i and 12. The two plates 69 and 69 have longitudinal grooves 15 and 16 respectively, of the width of the picture portion of the film so that the film-may be drawn between the plates 69 and 69 without sor'at'chingthe picture portion.

A leaf spring 11, fixed on the top' plate 99, bears against the bottom of the housing 6|..and presses the plates 69 and 69' together. In order to release this pressure, a cam 19 is fixed on a stub shaft 19 journalled in a projection 99 on the plate 69. This shaft 19 may be rotated by a handle 9| to move the cam 19 into contact with a portion of the plate 69 to raise the top plate 69 against the pressure of the spring 11. Two aprons 93 suitably secured one on each side of the sleeve 66 hold any excess film.

A sleeve 94 is vertically slidable in the sleeve 66 beneath the aperture 92 and a lens cell 96, carrying an objective 96, is threaded in the bottom end of the sleeve 84. A pin 91 is fixed in the wall of the sleeve 94 and projects laterally through a vertical slot 98 in the sleeve 66. In order to move the pin 91, sleeve 94 and objective 96 vertically for focussing. a third sleeve 99, having a helical cam slot 99 engaging the pin 91, is rotatably mounted on the outside of the sleeve 66. The top of the sleeve 99 abuts against a shoulder 9| on the sleeve 66 and is held against this shoulder by a collar 92 threaded on the bottom of the sleeve 66. The sleeve 99 is thus free to rotate but is held against axial movement on the sleeve 66.

Between the fins 96', the carriage 21 is provided with two spaced horizontal ribs 94 and 96. A bushing 96 is rotatably Journalled in these two ribs 94 and 96 and a pulley 91 is secured on the bushing 96 between the ribs by a a set screw 99. A belt 99, which may consist of a flat steel strip, passes over the pulley 91, through the openings 49 and engages in an annular groove I99 in the sleeve 99. Thus rotation of the pulley 91'causes rotation of the sleeve 99 and longitudinal focussing movement of the lens 96.

In order to rotate the pulley 91, a square rod I9I passes vertically through the housing 91 and through a square central bore I92 in the bushing 96. The top of this rod MI is journalled in a cap I99 fixed on top of the column 26 and the bottom of the rod ml is fastened in a bushing I94 rotatably mounted in the easel I6. A large wheel I96 is fixed on the bottom of the rod I9l beneath the easel I6 for rotating the rod to focus the lens 96.

In the modification shown in Fig. 9, a bevel gear I96 is attached on the bottom of the rod III and is engaged by a second bevel gear I91 mounted on a horizontal shaft I99. This shaft I99 is rotatably mounted in brackets I99 beneath the easel I6 and extends underthe easel to a point adjacent the eyepiece of the microscope. A knob II9 on the end of the shaft I99 serves to rotate this shaft.

The operation of my improved photographic enlarger is as follows. The operator places a film in the film gate and then places the film gate in the enlarger. The film gate is opened by means of the handle 9| and cam 19 to relieve the tension on the film and the film is moved back and forth to select the picture to be enlarged.

The entire projector is then raised or lowered on the column 26 by means of the knobs 96 until the desired amount of enlargement is obtained. During this movement, the rod I9I slides freely in the bore I92 of the bushing 96. The operator then places his eye at the eyepiece of the microscope and rotates the wheel I96 or knob I96 until the enlarged image of the film is in exact focus at the plane of the printing paper. The operator canthen proceed to make his prints in the manner.

The usual filter III is mounted in a frame H2 secured on ashaft 9. This shaft. 1 I9 is rotatably'secured in 'the housing 91 and lamp chamber 49 so that'the filter I II maybe swung into or out of the image forming light beam from the projector. The filter II I is of a color to which the enlarging paper is not'sensitive .so that with the filter III in place in the beam, the paper can be positioned with respect to the image without fog8ing.

From the foregoing, it will be apparent that I am able to attain the objects of my invention and provide a photographic enlarger having a simple, yet convenient and effective means for insuring accurate focus. While I have illustrated my enlarger as having a focussing microscope built into the easel, it is obvious that the microscope could be an accessory on the easel. The focus control mechanism would be equally effective and convenient with either type. Various modifications of structure and arrangement of the parts and elements can, of course, be made carried by said base and extending upward through the opening in said pulley for rotating said pulley, a housing secured at one end to said carriage and extending forwardly over said surface, a lamp chamber secured in the forward end of said housing, a reflector housing carried by said lamp chamber, a reflector within said reflector housing for directing light from said lamp chamber to said surface, an object support carried by said reflector housing beneath said reflector and in the path of the directed light,an objective adjustably carried by said reflector housing beneath said object support, means for adjusting said objective toward and from said object support to focus an image of an object on said support on said surface, and means operatively interconnecting said pulley with the last named means whereby rotation of said shaft adlusts said objective for focussing.

2. A photographic enlarger comprising a hollow base, a flat photo-sensitive sheet support carried by said base, said support having an aperture therethrough, means within said base for receiving light from said aperture and directing it in a direction parallel to said support, an objective mounted within said base in the path of the directed light and positioned so that its object plane coincides with the plane of a photosensitive sheet on said support, an ocular car- .ried by said base and extending beyond said support for receiving the image formed by said objective, an upright column carried by said support, a projector carried by said column, a projection lens adjustably mounted on said projector for projecting an image onto said support, a rotary sleeve for adjusting said lens for focussing, a vertical shaft rotatably carried by said base, means for operatively interconnecting said shaft and said sleeve whereby rotation of said shaft actuates said sleeve, and means carried by said base adjacent said ocular and operatively connected to said shaft for rotating said shaft.

3. A photographic enlarger comprising a base having a flat surface for receiving a photo-sensitive sheet, a substantially vertical column carried by said base, a carriage vertically slidably mounted on said column, means for sliding said carriage, a pulley rotatably mounted on said carriage, said pulley having a non-circular aperture therethrough, a vertical, non-circular rod rotatably carried by said base adjacent said column and slidably engaging in said aperture to actuate said pulley, means for actuating said rod, a projector mounted on said carriage and extending over said surface, an objective lens adjustably mounted on said projector for projecting images on said surface, a sleeve rotatably mounted on said projector and operatively connected to said objective for adjusting said objective to focus said images, and means for transmitting rotary motion from said pulley to said sleeve.

4. A photographic enlarger comprising a base having a flat surface for receiving a photo-sensitive sheet, said surface having an aperture therethrough, means positioned within said base for deflecting light from said aperture in a direction parallel to said surface, a microscope mounted within said base in the path of the deflected light, the object plane of said microscope being co-incident with the plane of a photo-sensitive sheet on said surface and the eyepoint of the microscope being adjacent an edge of said surface, an upright column mounted on said base, an image Projector carried by said column above said surface, a lens adjustably mounted on said projector, actuating means for adjusting said lens to focus an image on said surface, and means carried by said base adjacent said microscope, and operatively connected to said actuating means for driving said actuating means to focus said lens.

5. A photographic enlarger comprising a substantially fiat easel, an upright column mounted on said easel, a carriage vertically adjustably mounted on said column, means for adjusting said carriage, a projector mounted on said carriage and extending outward over said easel, an objective lens vertically adjustably mounted on said projector for focussing a projected image on said easel, a member rotatably mounted on said projector for adjusting said lens, a pulley rotatably mounted on said-carriage, said pulley having a non-circular bore therethrough, a vertical, non-circular rod rotatably carried by said easel and slidably engaging in said bore, means for transmitting rotary motion from said pulley to said member, and means adjacent an edge of said easel for actuating said rod.

6. A photographic enlarger comprising an easel, a vertical column mounted on said easel, a carriage vertically slidably mounted on said column, a tubular housing secured at one end to said carriage and extending forwardly therefrom over said easel, a lamp chamber secured in the other end of said housing, a vertical wall having an aperture therein forming one side of said lamp chamber, a reflector housing secured to said wall, means for insulating said reflector housing from said lamp chamber, said reflector housing having a first opening in alinement with the aperture in said wall and a second opening facing said easel, a reflector mounted in said reflector housing facing said openings for receiving light from said first opening and directing it through the second opening toward said easel, an objective lens mount carried by said reflector housing beneath said second opening and in spaced relation thereto, an objective lens adjustably secured in said mount, a film gate removably mounted in the space between the second opening and the lens mount, and means for adjusting said lens to focus an image of a film in said film gate on said easel.

7. A photographic enlarger comprising a base, a column rigidly secured on said base, a projection apparatus slidably mounted on said column for movement toward and from said base, an objective lens adjustably mounted in said projection apparatus, actuating means for adjusting said objective lens for focusing, a flat support carried by said base in alignment with said objective lens for receiving a photosensitive sheet, said surface having an aperture therethrough, a microscope carried by said base beneath said surface, said microscope being fixed with its object plane coincident with the plane of a photosensitive sheet on said surface and its eyepoint adjacent the edge of the surface, adjusting means carried by said base adjacent said surface and means for operatively interconnecting said adjusting mechanism and said actuating means whereby operation of said mechanism adjusts said lens.

8. An enlarging projector comprising a lamp housing having a front wa1l, a source of light mounted therein, said lamp housing having an opening in said front wall in alignment with said source, a flange on said front wall surrounding said opening and projecting outwardly thereirom, a reflector housing having an aperture therein larger than said flange, means for securing said reflector housing to the front wall of said lamp housing in spaced relation thereto and with said flange extending into said reflector housing through said aperture, a light deflector mounted within said reflector housing in alignment with said aperture for receiving light from said source and directing it downward at an angle, means on said light deflector for radiating heat to the reflector housing, the interior of said reflector housing being heat absorbing, heat dissipating means on the outside of said reflector housing, said reflector housing having a second aperture beneath and in alignment with said light deflector, means carried by said reflector housing for supporting an object to be projected beneath and in alignment with said second aperture, and an objective lens carried by said reflector housing in alignment with said object supporting means.

GUSTAVE FASSIN. 

